Abstract P4-07-58: Adjuvant Endocrine Therapy adherence in Breast Cancer patients and the Brazilian National Health System
Authors: ANA CRISTINA HERRERA, Caio C. Kasai, Eduarda T. Gonçalves, Liemi A. Homa, Carlos Eduardo E. de Oliveira
Journal: Cancer Research (2023)

Abstract Introduction: Breast Cancer is one of the most prevalent malignant disease in women and its first line neo- and/or adjuvant treatment on hormone positive (HR+) subtypes is the endocrine therapy. Even though Adjuvant Endocrine Therapy (AET) had significantly increased overall survival in the long-run, some studies have reported suboptimal treatment adherence rates, varying from 40-95.7%. One possible cause for this great variability on AET adherence is the patients’ expenses on treatment. Recent studies have demonstrated that as the cost of treatment increases the treatment adherence decreases. Nonetheless, as far as the authors have searched, no studies have tried to understand such relationship in Brazil, where medications can be taken without any out-of-pocket expenses through the Sistema Único de Saúde (SUS), or through Health insurance companies; and through direct out-of-pocket expenses. Methods: This was an observational cross-sectional pilot study, carried out with an online questionnaire applied to patients from the Centro de Tratamento Oncológico Pro Onco [Pro Onco Oncological Treatment Center] and Centro de Apoio ao Paciente com Câncer de Londrina [Londrina Cancer Support Center] (State of Paraná, Brazil). The questionnaire applied in this study included objective questions that aimed to understand the systemic endocrine therapy adherence among Breast Cancer patients. In order to do that, the Morisky-Green (MG) test was used. A linear regression model was built using the MG test as dependent variable, and how the patients obtained the drugs as independent variable, controlled by other sociodemographic and clinical covariates. Results: Between December 2021 and March 2022, 95 patients were included in this study. Mean age was 50.71 (SD = 10.00) and mean age at diagnosis was 45.86 (SD = 8.66). Patients obtained the drugs mainly via Health Insurance (45 patients or 47.37%), followed by the SUS (44 patients or 46.32%) and private health expenses (6 patients or 6.32%). It was found that how the patient obtained the medication was statistically significant in predicting adherence. Patients that obtained the medication via the SUS had poorer adherence compared to those that obtained the medication via Health Insurance (coeff.=-0.38 [-0.68;-0.09]; p-value = 0.010) and via Private Health Expenses (coeff.=-0.81 [-1.42;-0.21]; p-value = 0.008). It was also found that considering all three main options available to obtain the medication, 30 patients (68.18%) that obtained the medication via the SUS had already forgotten to take the medication once; whereas only 18 patients (40%) that obtained the medication via Health Insurance had done (Chi-Square = 7.1116; p-value = 0.008). Besides that, it was found that only 22 patients (50%) that obtained the medication via the SUS knew the type of cancer they had. Considering only patients that obtained the medication via Health Insurance, 35 patients (77.78%) knew the type of cancer they had (Chi-Square = 7.4546; p-value = 0.006). Conclusion: The results of this study do not match the literature on the topic, and it could be explained by a poorer doctor-patient relationship at SUS as non-clarification on the importance of adjuvant treatment can be related to a poorer adherence. Citation Format: ANA CRISTINA HERRERA, Caio C. Kasai, Eduarda T. Gonçalves, Liemi A. Homa, Carlos Eduardo E. de Oliveira. Adjuvant Endocrine Therapy adherence in Breast Cancer patients and the Brazilian National Health System [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-58.